09_ag - Agriculture: Terms Agriculture “Agriculture is...

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Unformatted text preview: Agriculture: Terms Agriculture “Agriculture is the deliberate modification of the Earth’s surface through cultivation of plants and rearing of animals to obtain sustenance or economic gain.” “Cultivate” means “to care for.” Any cultivated plant is called a crop. Origins of Agriculture Subsistence & Commercial Agriculture Agricultural Regions Economic & Cultural Issues 1 2 Hunters & Gatherers The Pre-Agricultural World About 0.005% of humanity today live an exclusively hunter-gatherer lifestyle. Based on what we know about them, and on archaeological evidence, we can make some statements about what most people did before agriculture: Human beings – or something very like human beings – have been around for at least two million years. But we’ve only been practicing agriculture for something like 10,00020,000 years. Before agriculture there was what we call hunting and gathering. Small groups (less than 50 people), low population density. Gathering is usually much more important than hunting (usually 60% to 80% of the food). In most societies men hunt and fish, and women gather. Getting food usually takes no more than 10% of people’s time. Politics are informal, consensus based; little social stratification; beliefs are animistic. Limited material culture; no permanent settlements. Strong ties to land, but nomadic and mobile. 3 Origins of Agriculture 4 What is “domestication?” We can never know where agriculture began – it began in prehistory, and it probably began in more than one place. However, historians, archaeologists, agronomists, geographers and other scholars have worked for over a century now trying to determine just where the processes that lead to agriculture – and to civilization – began. Some of the changes that take place when plants are domesticated: – Gigantism (bigger seeds or fruits) – Loss of seed dispersal mechanisms – Loss of bitter or toxic substances – Changes in floral structures or pollination schemes – Changes in flowering cycle – Diversity of form – Loss of mechanisms to protect against predators 5 Information source: http://hcs.osu.edu/hcs200/Notes1.htm 6 1 Origins of Agriculture Carl Sauer’s theory: – Not in response to hunger. – Not among nomads. – Not in grasslands or river valleys. – In places of high environmental diversity. – In places of high plant diversity. – Beginning with vegetative reproduction (roots), not grains. ∴ SE Asia 14,000-35,000 BP First Vegetative Planting More conventional theory: According to Sauer, the earliest vegetative agriculture appeared in Southeast Asia, and probably involved root vegetables like taro and yams, and perhaps tree crops like bananas. Vegetative agriculture then diffused throughout Asia and eventually to the Near East and Europe. Other, perhaps independent inventions took place in Africa (oil palm, yam) and South America (manioc, arrowroot). – As a consequence of gathering seeds, gatherers noted which plants produced best, and began (perhaps accidentally) to care for them. – Agriculture began with crops like grains, lentils and possibly dates. – Agriculture began in the river valleys – the Tigris & Euphrates, the Nile, the Indus, the Huang He, and the high valleys of Mexico and Peru. ∴ Near East 10,000-20,000 BP 7 8 First Seed-Based Agriculture Origins: Vegetative Hearths Seed-based agriculture began in at least three places according to Sauer: – Western India – Northern China – Ethiopia It diffused quickly from India to the Near East, then to Europe. Seed-based agriculture also developed independently in Mexico and Northern Peru. 9 Origins: Seed-Based Hearths 10 Origins of Selected Crops 11 12 2 Subsistence vs. Commercial vs. Contrasting Theories Your book doesn’t mention them, but at least two other people should be included here: Subsistence and commercial agriculture differ in five ways: – Nikolai I. Vavilov (1887-1943) Looked for “centers of diversity,” which he believed were also “centers of domestication.” Collected more than 250,000 seed samples; identified 8 agricultural hearths: Southeast Asia; China; India; TurkeyIran; Mediterranean; Ethiopia; Mexico/Central America; Andes/Brazil/Paraguay. – Jack R. Harlan (1917-1998) Agronomist and geneticist; actually met Vavilov at a meeting in Washington in 1932. Defined – Three "centers": the Near East, Northern China, and Meso America. – Three “non-centers”: S.E. Asia, S. America, and Africa 13 Labor Force In Agriculture – PURPOSE (consumption vs. off-farm sales) – PERCENTAGE OF FARMERS (majority vs. minority of population) – MACHINERY (mostly hand vs. mostly mechanized) – FARM SIZE (small vs. large) – FARMS AND OTHER INDUSTRIES (mostly isolated vs. highly integrated) 14 Tractors per 1,000 15 Agricultural Regions of the World 16 Climate & Agriculture Regions Climate and agriculture regions are similar – but not identical. 17 18 3 Subsistence Agriculture: Shifting Cultivation Also known as “slash and burn.” Most common today in tropical areas (adaptation to poor soils). Small-scale, no machines. Temporary – short occupation, long fallow period. Crops vary from region to region. Only 5% of the world’s population practice shifting cultivation. Slash & Burn: Effects 1986 1992 Farmers clear land and burn the debris. Poor soils can only support crops for two-three years. Source: http://science.nasa.gov/headlines/y2003/16may_biocorridors.htm 19 Subsistence Agriculture: Pastoral Nomadism Based on herding domesticated animals. Adapted to dry climates where other types of agriculture are basically impossible. Mostly in North Africa, Near East and Central Asia Choice of animals varies – dromedary camels, sheep and goats in North Africa and Arabia, bactrian camels and horses in Central Asia, etc. 1975 Subsistence Agriculture: Intensive, Wet Rice Dominant Practiced in areas of high population density – East, South and Southeast Asia. Extremely small farms, worked by hand (few machines), focused on rice. Rice is unique: it can grow in water (well, in flooded fields). Flooded fields have many advantages: pest control, easy fertilizing, fish production. Where climate is favorable, farmers can double crop – raise more than one crop per field per year. Nomads don’t just “wander” – precise migration patterns, strong sense of territory. Some nomads practice transhumance: seasonal migration up and down mountains. Source: http://www.loc.gov/exhibits/empire/ethnic.html Sources: http://encarta.msn.com/media_461550731_761582457_-1_1/Satellite_Images_of_Deforestation.html; http://maps.google.com/?ie=UTF8&om=1&z=9&ll=-10.622817,-62.20459&spn=1.573774,3.010254&t=k 20 21 Subsistence Agriculture: Intensive, Wet Rice Not Dominant Wet rice (“paddy” or “sawah” grown) cultivation is complex: – Rice seed is planted in a nursery, and raised until ready to be transplanted. – Fields are prepared and plowed. – Fields are flooded. – Individual seedlings are planted, individually, by hand, in the field. – Each plant is cared for individually until harvested, by hand, with special knives. Source: http://pubs.usgs.gov/publications/text/tectonics.html 22 European Crop Rotation This is a very ancient form of agriculture – think of places like Medieval Europe, or rural Latin America, as well as more arid parts of South and East Asia. Widely practiced in areas where climate doesn’t support wet rice. Similar in many ways to areas where wet rice dominates, but emphasizes different crops (wheat, barley, corn, etc.). In these areas farmers practice crop rotation to increase yields and maintain the health and fertility of their farms. Source: http://www.pfpcanada.com/research.htm 23 24 4 Commercial Agriculture: Mixed Crop & Livestock Farming Integration of livestock (sheep, cattle, goats, chickens etc.) and crop farming. Most crops raised are fed to animals. Most land is devoted to crops. Most money is generated from animals and animal products. Commercial Agriculture: Dairy Farming Dairy products (butter, cheese, etc.) are extremely valuable. Mostly produced in Western Europe, North America, Russia, Australia and New Zealand. Because milk is extremely perishable, dairy operations traditionally located near markets – in the milkshed. Advantages: – Livestock supply manure to fertilize the crops. – Workload can be more evenly distributed throughout the year. – Less seasonal variation in income. Source: http://www.epa.gov/esd/land-sci/trends/eco64/eco64_samp57.htm 25 Today, transportation makes it possible for milk producers to locate hundreds of miles from markets. However, the further from markets, the less likely dairy operations are to produce fluid milk. Source: http://clinton.senate.gov/issues_agriculture.html 26 Commercial Agriculture: Grain Farming US Dairy Production, by Region Grains – wheat, corn, oats, barley, rice, etc. – are grasses. Globally, the most important crop grown is wheat – more wheat is exchanged in international commerce than any other grain (most rice is consumed where it is produced). Wheat is usually produced in areas where it is too dry for mixed farming. The US is the largest grain producing region on earth. – Winter wheat region (wheat planted in fall, dormant through winter, grows and is harvested in late spring or summer). – Spring wheat region (wheat planted in spring, harvested in late summer). – Other wheat regions (Eastern Washington) Other major producers include Canada, Argentina, Australia, France and the UK. Large scale production only became possible in the 19th century, with the development of mechanized agriculture. Source: http://thesocietypages.org/graphicsociology/tag/agriculture/ 27 Commercial Agriculture: Mediterranean Agriculture Adapted to the Mediterranean climate region – warm dry summers, mild wet winters (this is a very odd pattern – most places get plenty of precipitation in summer). Most crops grown for human consumption – not animal feed. Primary source of the world's olives, grapes, etc. 28 Commercial Agriculture: Livestock Ranching Ranching is, in some ways, the commercial version of pastoral nomadism. Ranching is a type of commercial agriculture adapted to areas which are too dry for other forms of agriculture. Ranching is not as profitable per acre as farming – if irrigation makes farming possible, ranching usually ends. Wheat and other grains are also grown in traditional Mediterranean areas (but mostly for local consumption). Animals and animal products of less importance (at least traditionally). Source: http://www.usaid.gov/wbg/asalah.htm Source: http://water.usgs.gov/pubs/circ/circ1225/html/cover.html 29 30 5 US Cattle Ranching Ranching Today Some cattle are still raised on ranches, but most are on shifting pastures. Many cattle are now shipped to feed lots for fattening near their market. Ranching is also practiced in other developed countries: Cattle ranching in the US begins with Columbus's second voyage. – Cattle ranching was small scale on the East Coast in the 16th to 18th centuries. – Rapidly expanding cities became major markets for beef. – In the Western US, semiarid areas could be used to produce beef cattle – the problem was getting the beef to market. – The solution – long-distance cattle drives, from rural areas to the nearest railroad. – By the end of the 19th century, cattle drives were basically over. – Spain and Portugal. – Argentina, Brazil, Uruguay. – Australia. End of open range. Expansion of railroads. Changes in cattle breeding. Cattle ranching changed to mostly fixed location ranching. Source: http://www.ndsu.nodak.edu/instruct/isern/431/cattle.htm 31 Commercial Agriculture: Commercial Gardening (or “Truck Farming”) Farming” Truck farming has nothing to do with trucks or trucking! The word "truck" comes from an old English word meaning "to carry" or "to exchange." Specialty fruit and vegetable farming – very similar to "market gardening." Fresh fruits and vegetables – perishable produce. Farmers tend to specialize in a few profitable crops. Traditionally grown near markets. Commercial Agriculture: Plantation Agriculture Plantations today are almost always in the tropics, and in less developed countries. Outside, often absentee owners. Labor may be imported to an otherwise uninhabited area. Crops are grown almost exclusively for sale in distant markets – mostly in developed countries. Specialization in one or two crops (for example, bananas, tea, coffee, oil palm, teak, sugar, rubber, tobacco, etc.). With modern transportation, areas like California's Central and Imperial Valleys, Arizona's Gila River Valley, parts of Texas, Florida, Georgia, etc. have become truck farming areas for the whole country. Source: http://my.dmci.net/~kingcm/kingfamily/02-organicfarming.html 33 Agriculture & the Environment Agriculture is severely constrained by: – – – – Sources: http://www.photolib.noaa.gov/coastline/line0419.htm; http://sofia.usgs.gov/sfrsf/rooms/nutrients/controls/bmp/; http://www.ars.usda.gov/is/AR/archive/oct98/odor1098.htm 32 Climate Terrain Soil Yes, it's possible to grow tomatoes in Iceland or lettuce in Saudi Arabia – but it's expensive, and takes sophisticated technology. Sources: http://www.photolib.noaa.gov/coastline/line0419.htm; http://edcdaac.usgs.gov/glcc/fao/ 34 Soil Salinization Salinization is the concentration of salts in topsoil. Salinization occurs naturally in arid areas. Poor agricultural practice — especially in arid climates — can turn fertile farms into a wasteland. Agriculture can have a strong – even devastating – impact on the natural environment: – Slash-and-burn agriculture (if poorly done, can ruin forest lands for years) – Overgrazing (can cause soil loss, erosion) – Desertification (agriculture practiced on marginal lands can degrade land, expanding arid areas) – Irrigation Salinization Waterlogging Severe salinization, San Joaquin Valley Source: http://www.ars.usda.gov/is/pr/2004/040902.htm?pf=1S 35 36 6 Global Soil Degradation (all sources – salinization, topsoil loss, etc.) Agriculture and Economics: Subsistence Agriculture Population growth: – A rising population means that subsistence farmers must produce more food. – According to Esther Boserup, this means that they will use newer, more intensive forms of agriculture to increase yield. – Great idea – except that it's not possible in all areas, due to environmental factors. International trade: – The idea of talking about "subsistence" and "trade" seems contradictory – but many subsistence farmers do produce cash crops. – The most popular (and most profitable): drugs. 37 Coca production regions in Peru Source: http://www.usdoj.gov/dea/pubs/intel/01012/01012.html 38 Problems in Commercial Agriculture Agriculture and Economics: Commercial Agriculture Overproduction – Commercial farmers suffer from low incomes because they produce too much. – In developed countries, modern crop varieties, machines, chemicals, etc. have increased yields enormously - the greater the supply, the lower the price. – Most governments in the developed world have instituted farm subsidy policies to either protect domestic producers or limit production. In 1826 Johann Heinrich von Thünen noticed something interesting - identical physical characteristics (climate, soil) didn't mean identical crops. The crops farmers chose to plant were determined by: – Crop value – Land value – Cost of transportation Sustainable Agriculture – This includes organic farming as well as various forms of integrated pest management. – Various techniques, including ridge tillage, limited use of pesticides and herbicides, and integration of crops and animal production. Von Thünen's model did not take into account any actual site factors - rivers, roads, etc. - but the model can be modified to deal with them. The model is still useful - it helps explain why farmers choose the crops they do, where it makes sense to produce lowvalue bulky commodities, and where it doesn't, etc. Off-farm migration – In many areas of the developed world it has become difficult to get people to stay in farming regions. – This leads to greater dependence on migratory labor, absentee ownership, and consolidation of farms and farming. 39 Problems in Commercial Agriculture 40 Monoculture & Disease Loss of crop diversity – Replacement of genetically diverse local varieties with hybrid seed. – Loss of unique disease, climate and pest resistance. – Loss of genetic resources. By replacing local varieties (“land races”) with new, improved crops, productivity can be greatly increased. But the new improved crops may lack resistance to disease – and since everybody grows the new crops, everybody’s at risk. 41 Source: http://environment.newscientist.com/channel/earth/mg19425983.700 42 7 Monoculture: Disaster Increasing Food Supplies Gros Michel banana The bananas that you eat today are not the bananas that your grandparents ate. All commercial bananas are seedless – they reproduce from “roots.” In essence – they’re clones. When disease strikes, all bananas from the same clone will be equally vulnerable. Possible strategies: Cavendish banana Unfortunately, bananas are susceptible to many diseases – Panama disease, Black Sigatoka disease, Banana Bunchy Top Virus, etc. When Panama disease wiped out the commercial crops of Gros Michel, growers switched to Cavendish. Now that Cavendish is in trouble, growers are looking for something new – but they haven’t found it yet. Sources: http://wwwchem.uwimona.edu.jm:1104/lectures/banana.html; http://en.wikipedia.org/wiki/File:Bananas.jpg –Diet modification (shift to less harmful food sources). –Expanding agricultural land. –Increasing the productivity of agricultural land. –Identifying & exploiting new food sources. –Increasing exports. 43 44 Diet Modification Animals like cows, pigs and sheep consume far more energy (and resources like water) than they provide as food. Enormous amounts of pollution are created in commercial livestock production. A shift to vegetable protein sources would be more efficient and result in less waste. Problems: – Livestock production is frequently the only agricultural activity that’s possible in many areas (it’s hard to raise soybeans in a desert). – Large scale commercial agriculture is also a significant source of waste and pollution. Sources: http://www.nytimes.com/2008/01/27/weekinreview/27bittman.htm?_r=2&oref=slogin&oref=slogin; http://www.tucsonweekly.com/gbase/Opinion/Content?oid=oid%3A107527 45 Expanding Agricultural Land Sources: http://www.nytimes.com/2008/01/27/weekinreview/27bittman.htm?_r=2&oref=slogin&oref=slogin 46 Arable Land Per Capita Only about 11% of the world’s land is currently being used for agriculture. By increasing the area in production, we can expand the food supply. Problems – Environmental problems (desertification, waterlogging) have made some farmland unusable. – Expanding urban areas frequently take farmland out of production. – Most of the earth’s remaining land is not suitable for agriculture – too hot, too cold, too steep – without enormous modification and improvement. 47 Source: http://www.unep.org/Geo2000/english/i76a.htm 48 8 New Food Sources Increasing Productivity We get most of our food from a very limited number of plants and animals – rice, wheat, corn, sorghum and millet, potatoes, sweet potatoes, cows, pigs, chickens and sheep. By expanding our horizons we can gain access to enormous new resources. Strategies We have already made enormous improvements in productivity – better fertilizers, pesticides, herbicides, farm machinery – and better plants through the green revolution. By continuing to improve technologically (especially with genetically modified crops), we can increase food supplies for the foreseeable future. Problems – Ocean farming (aquaculture) – New high-protein cereals – Encourage use of underused foods Problems – Hybrid seed, fertilizers, pesticides, farm machinery, etc. are expensive, and may be impossible for poor farmers to afford. – Genetically modified crops are controversial, and may be unacceptable. 49 Aquaculture: Farming the Seas – Most of the strategies are enormously more difficult than our current approaches – which is why haven’t been doing them. – In many cases they require expensive inputs of energy and resources, and may require people to change their way of life. 50 High-Protein Cereals Golden rice “Green Revolution” rice Eastern gamagrass Sources: http://aquaculture.noaa.gov/; http://www.noaanews.noaa.gov/stories2006/images/aquaculture-hawaii-kona-blue07-2006b.jpg; http://www.lib.noaa.gov/docaqua/reports images/yarish6.jpg 51 New Food Sources 52 Increasing Food Exports As productivity increases around the world, countries that once had to import food can become food exporters – and the price of food will come down. Problems Cuphea species for oil Amaranth species for grain, oil, and vegetables – Not all areas can produce surpluses, even with new crops or techniques. – Increasing reliance on foreign sources of food is a potential political problem, as well as a source of economic uncertainty. Indian Rice Grass flour Sources: http://www.ars.usda.gov/is/AR/archive/dec99/crop1299.htm; http://businessresources.mt.gov/BRD_RCT_Success.asp; http://www.ars-grin.gov/ars/MidWest/Ames/repository/oldsitearchive/Crops_New/Amaranth.html Sources: http://usinfo.state.gov/journals/ites/1005/ijee/buell.htm; http://www.ars.usda.gov/is/timeline/green.htm; http://www.ars.usda.gov/is/timeline/green.htm 53 54 9 Sources: http://www.fao.org/SD/EIdirect/gis/EIgis000.htm; ftp://ftp.fao.org/docrep/fao/009/a0750e/a0750e00.pdf 55 10 ...
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